diff --git a/src/gui/widgets/plot.py b/src/gui/widgets/plot.py
index 5668de9..3a52377 100644
--- a/src/gui/widgets/plot.py
+++ b/src/gui/widgets/plot.py
@@ -17,9 +17,10 @@ class PlotWidget(BasePlotWidget):
         stage_diff = np.diff(dataframe[stage])
         start_index = np.where(stage_diff == 1)[0]
         finish_index = np.where(stage_diff == -1)[0]
-        if start_index:
+
+        if start_index.size:
             start_timestamp = times[start_index[0]]
-            finish_timestamp = times[finish_index[0]] if finish_index else times[len(times) - 1]
+            finish_timestamp = times[finish_index[0]] if finish_index.size else times[len(times) - 1]
             region = pg.LinearRegionItem([start_timestamp, finish_timestamp], movable=False)
             region.setBrush(pg.mkBrush(self._stage_colors[stage]))
             return region